Process for the preparation of polymers of α-olefins

Abstract

A solution polymerization process for the preparation of homopolymers of ethylene and copolymers of ethylene and higher α-olefins and a coordination catalyst for such a process are disclosed. In the process monomer is polymerized in the presence of the coordination catalyst which consists of a particular admixture of (a) a solution of an organoaluminum compound and an organomagnesium compound, with (b) a solution of a titanium compound and a vanadium compound. The catalyst exhibits relatively high activity in the polymerization of the monomers.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows: 
     
       1. A solution polymerization process for the preparation of high molecular weight polymers of α-olefins selected from the group consisting of homopolymers of ethylene and copolymers of ethylene and higher α-olefins, said process comprising feeding α-olefin monomer, a coordination catalyst and inert hydrocarbon solvent to a reactor, and separating the polymer thus obtained, said coordination catalyst being an admixture of (A) a solution of an organoaluminum compound and an organo-magnesium compound in inert hydrocarbon solvent, and (B) a solution of a titanium compound and a vanadium compound in inert hydrocarbon solvent, such that in the admixture (a) the atomic ratio of Al:Mg is in the range 0.1-20, (b) the atomic ratio of Ti:V is in the range 0.5-6, (c) the atomic ratio of (Al+Mg):(Ti+V) is in the range 1.1-2.5 and (d) the sum of the expressions Al/(Al+Mg) and Ti/(Ti+V), on an atomic basis, is in the range 0.7-1.4, said organoaluminum compound being selected from the group consisting of alkenyl aluminum, where the alkenyl group has 4-20 carbon atoms, AlR 3  and AlR 2  H where each R is alkyl, cycloalkyl or aryl-substituted alkyl of 1-20 carbon atoms, said organomagnesium compound being MgR 2  where each R is as defined, said titanium compound being of the formula TiX n  (OR') 4-n  where X is chlorine or bromine, R' is alkyl or aryl-substituted alkyl having 1-20 carbon atoms and n is 0-4, and said vanadium compound being selected from the group consisting of VX m  (OR') 4-m  and VOX p  (OR') 3-p , where m is 0-4 and p is 0-3. 
     
     
       2. The process of claim 1 in which the higher α-olefin has 3-10 carbon atoms. 
     
     
       3. The process of claim 2 in which the titanium compound is selected from the group consisting of TiCl 4  and TiBr 4  and the vanadium compound is selected from the group consisting of VCl 4 , VBr 4  and VOCl 3 . 
     
     
       4. The process of claim 3 in which the organoaluminum compound is selected from the group consisting of alkenyl aluminum and AlR 3  ", where the alkenyl group has 4-10 carbon atoms and each R" is alkyl of 2-8 carbon atoms, and the organomagnesium compound is MgR 2  '" where each R'" is alkyl of 2-8 carbon atoms or aryl-substituted alkyl of 7-14 carbon atoms. 
     
     
       5. The process of claim 4 in which the titanium compound is TiCl 4 , the vanadium compound is VOCl 3  and the organomagnesium compound is MgR 2  '" where each R'" is alkyl of 2-8 carbon atoms. 
     
     
       6. The process of claim 5 in which, on an atomic basis, the ratio of Al:Mg is in the range 0.1-20, the ratio of (Al+Mg):(Ti+V) is in the range 1.1-2.0 and the sum of the expressions Al/(Al+Mg) and Ti/(Ti+V) is in the range 0.8-1.4. 
     
     
       7. The process of claim 5 in which the organo-aluminum compound is isoprenyl aluminum. 
     
     
       8. The process of claim 5 in which the higher α-olefin has 4-8 carbon atoms. 
     
     
       9. The process of claim 5 in which the coordination catalyst is admixed prior to being fed to the reactor. 
     
     
       10. The process of claim 5 in which the polymer thus obtained has a density in the range 0.910-0.970 g/cm 3  and a melt index in the range 0.1-200. 
     
     
       11. The process of claim 10 in which the polymer thus obtained is an ethylene homopolymer. 
     
     
       12. The process of claim 10 in which the polymer thus obtained is a copolymer of ethylene and a higher α-olefin. 
     
     
       13. The process of claim 5 in which the hydrocarbon solvent is selected from the group consisting of hexane and cyclohexane. 
     
     
       14. A coordination catalyst for the polymerization of α-olefins, said catalyst consisting of an admixture of (A) a solution of an organoaluminum compound and an organomagnesium compound in an inert hydrocarbon solvent; and (B) a solution of a titanium compound and a vanadium compound in an inert hydrocarbon solvent, such that in the admixture (a) the atomic ratio of Al:Mg is in the range 0.1-20, (b) the atomic ratio of Ti:V is in the range 0.5-6, (c) the atomic ratio of (Al+Mg)(Ti+V) is in the range 1.1-2.5 and (d) the sum of the expressions Al/(Al+Mg) and Ti/(Ti+V), on an atomic basis, is in the range 0.7-1.4 said organoaluminum compound being selected from the group consisting of alkenyl aluminum, where the alkenyl group has 4-20 carbon atoms, AlR 3  and AlR 2  H where each R is alkyl, cycloalkyl or aryl-substituted alkyl of 1-20 carbon atoms, said organomagnesium compound being MgR 2  where each R is as defined, said titanium compound being of the formula TiX n  (OR') 4-n  where X is chlorine or bromine, R' is alkyl or aryl-substituted alkyl having 1-20 carbon atoms and n is 0-4, and said vanadium compound being selected from the group consisting of VX m  (OR') 4-m  and VOX p  (OR') 3-p  where m is 0-4 and p is 0-3. 
     
     
       15. The catalyst of claim 14 in which the titanium compound is selected from the group consisting of TiCl 4  and TiBr 4  and the vanadium compound is selected from the group consisting of VCl 4 , VBr 4  and VOCl 3 . 
     
     
       16. The catalyst of claim 15 in which the organo-aluminum compound is selected from the group consisting of alkenyl aluminum and AlR 3  ", where the alkenyl group has 4-10 carbon atoms and each R" is alkyl of 2-8 carbon atoms, and the organomagnesium compound is MgR 2  '" where each R'" is alkyl of 2-8 carbon atoms or aryl-substituted alkyl of 7-14 carbon atoms. 
     
     
       17. The catalyst of claim 16 in which the titanium compound is TiCl 4 , the vanadium compound is VOCl 3  and the organomagnesium compound is MgR 2  '" where each R'" is alkyl of 2-8 carbon atoms. 
     
     
       18. The catalyst of claim 17 in which, on an atomic basis, the ratio of Al:Mg is in the range 0.1-20, the ratio of (Al+Mg):(Ti+V) is in the range 1.1-2.0 and the sum of the expressions Al/(Al+Mg) and Ti/(Ti+V) is in the range 0.8-1.4. 
     
     
       19. The catalyst of claim 17 in which the organo-aluminum compound is isoprenyl aluminum. 
     
     
       20. The catalyst of claim 17 in which the hydrocarbon solvent is selected from the group consisting of hexane and cyclohexane.